Low vision refers to any chronic, uncorrectable visual impairment that hinders everyday function. In the United States, age-related macular degeneration (AMD) is the leading cause of visual impairment in older adults. More than two million Americans 50 years and older suffer intermediate or advanced AMD. The condition causes damage in the central region of the retina, leading to scotomas that force the use of remaining eccentric vision for tasks formerly performed by the fovea. Specific regions of the eccentric retina are recruited as replacement for the original fovea, leading to development of preferred retinal loci (PRLs). Nevertheless, performing daily visual tasks and maintaining quality of life remain extremely challenging. Due to the severe impact of central vision loss on daily visual tasks, developing suitable visual rehabilitation based on a comprehensive and accurate assessment of their residual vision is vital for people with central vision loss. Such assessment is crucial for monitoring the status of vision loss, for developing and providing effective low vision rehabilitation interventions, and for obtaining projections of potential benefits from interventions. The proposed studies aim to tackle the technological challenges. We will develop new efficient adaptive procedures to measure a number of visual functions and their maps, and identify the core metrics of functional vision in low vision. The proposal has three specific aims. In Aim 1, we will develop and validate new adaptive methods for efficient assessment of metrics of functional vision in normal vision. This set of measures will serve as candidates for core metrics of functional vision. In Aim 2, we will refine the new adaptive methods developed in Aim 1 for applications in low vision. In Aim 3, we will model and evaluate the relationship between the candidate metrics and everyday visual performance, and identify the core metrics of functional vision in low vision. The proposed research addresses one of the major research needs/gaps identified by the NEI Low Vision and Blindness Rehabilitation Panel. Our overall objective is to develop time- and cost-efficient clinical outcome measures that provide a thorough and precise assessment of patients' functional vision. The innovative adaptive methods can also be employed for many medical purposes such as providing prognostic and diagnostic information, monitoring disease progression, and evaluating treatment and rehabilitation outcomes.